Out on a Limb

Students at the University of Washington in Seattle are using RFID tags to identify trees that have been genetically modified to grow quickly.

Graduate students at the University of Washington in Seattle have gone out on a limb with a project that involves embedding RFID transponders in trees. The idea might not be as wild as it sounds.

The university’s Precision Forestry Cooperative was set up with funding from the state legislature to use advanced technology to improve conservation techniques in the forestry Industry. In 2002, after two years of preparation, students embedded the tags in two-year-old saplings to see if RFID could be used to identify trees that have been genetically modified to grow more rapidly. The trees are planted and monitored. Eventually their seeds are harvested to create a new generation of faster-growing trees. Big money was invested in the genetic modification, so the seeds of the original saplings are very valuable.

“We have used plastic ribbons to mark trees, but the trees are often vandalized by hunters and others,” says Gerard Schreuder, acting director of the cooperative. “Embedded RFID tags are not visible, and they remain in the tree throughout its life.”

Students embedded a 134.2 kHz glass-encapsulated transponder from Texas Instruments in each sapling. Each tag has 80 bits of read-write memory, which can be used to store a serial number and other data about the sapling. A scientist with a handheld computer equipped with a reader can go to an area of the forest where genetically modified saplings have been planted, scan the tag and gather data on the tree in the field.

Trees grow from the top, so the transponders stay at the same height. New growth forms around the transponder, so it becomes completely embedded in the middle of the tree trunk. Because of the moisture in the tree, the only way to get a reading is with a low-frequency tag. That limits the read range to about 2 feet.

The limited read range is a shortcoming, but Washington’s forestry service is still interested in the system. The service is required by law to protect the trees in watersheds and along rivers and streams. Based on the university’s pilot, the service believes that RFID could help it more quickly identify trees in a particular area. An RFID system could also potentially reduce the amount of time, paperwork and money needed to gather data on millions of trees across the state.

Schreuder says the cooperative hasn’t taken the RFID research beyond the pilot stage, but he hopes to soon hire a new director who can pick up where the students left off. In the meantime, the project has piqued the interest of several forestry companies. In addition to employing RFID to monitor genetically modified trees, some are considering branching into new areas, such as using the tags to certify the quality of wood. Which suggests that RFID could, indeed, take root as a means of tracking trees.

Source : RFID Journal